1. Field of the Invention
This invention relates generally to syringes, and more particularly, but not by way of limitation, to hypodermic syringes that include apparatus for preventing exposure of the needle to people coming into contact therewith.
2. Background of the Invention
Many problems and injuries are associated with conventional hypodermic syringes due to human contact with the needle. Contact with the needle before it is used can contaminate the needle and any medication therein. Contact with the needle after it is used can result in the transmission of disease.
A conventional hypodermic syringe includes a syringe body, a piston member, a hypodermic needle and a needle cap. The needle cap is a tubular member removably attached to the needle hub over the sharp end of the needle. Due to the spread of infectious diseases such as hepatitis B and acquired immune deficiency syndrome (aids). most hypodermic syringes used today are designed for one use only and immediate disposal.
Although disposal of hypodermic syringes immediately after they are used reduces human exposure to contaminated needles, it does not eliminate all of the problems associated with hypodermic syringes. Health care personnel and others working in the health care environment still frequently stick themselves with the needles before, during and after they are used.
Needle sticks commonly occur when the user of the syringe attempts to put the cap back on the needle after it is used. Health care providers tend to recap needles to protect themselves, to alleviate patient fear and the like. Placing a conventional needle cap on a needle without scratching or pricking fingers can be difficult, particularly in the often stressful nature of health care environments.
Needle sticks also commonly occur when the needle must be removed from the syringe. There are many circumstances in which a used needle must be removed and replaced with a different needle before the syringe can be discarded. For example, when a blood culture is performed, the needle used for removing blood from a patient must be removed and replaced with a clean needle prior to transferring the blood from the syringe to the sterile culture bottle. Small needles used to withdraw blood from patients with small veins are often replaced with larger needles to prevent destruction of the blood cells upon transfer of the blood from the syringe to another container. In other cases, needles large enough to transfer the medication from the original container to the syringe are replaced by smaller needles required for certain procedures, e.g., controlled applications of anesthesia in repairing a wound. Removal of the needle directly by hand exposes the hand to contamination and often results in a needle stick. Of course, recapping the needle prior to its removal can also lead to a needle stick. Although instruments such as hemostats can be used to remove the needle, they have to be sterilized after they are used resulting in added time and expense. Also, such instruments are not always available when removal of the needle is required.
In addition, there are certain procedures associated with hypodermic syringes that currently require the user to work with his or her fingers and hands in very close proximity to the sharp end of the needle. For example, to inject medication into the medication port of equipment such as 3-way stop-cocks and Heparin locks, the user of the syringe must hold the relatively small medication port or attached equipment in one hand while using the other hand to maneuver the syringe and guide the exposed needle into the medication port. Any sudden movements by the patient or other disturbances can cause the user to miss the medication port with the needle and stick his or her hand or finger rendering the needle and medication contaminated.
Finally, health care personnel and others associated with health care environments are frequently stuck by needles that have been improperly discarded or inadvertently left lying on a work surface, dropped on the floor, etc.
In an attempt to prevent accidental needle sticks, many hospitals and other health care facilities have adopted policies that prohibit the practice of recapping needles after they are used. In addition, hypodermic syringes have been developed that include protective devices such as tubular shields that can be extended over the needle. Unfortunately, policies prohibiting needle recapping and protective needle shields do not prevent needle sticks when the needle has to be removed and when the syringe is used in connection with procedures that require use of the user's fingers and hands in close proximity to the needle. Needle shields must usually be retracted before the needle can be removed from the syringe or inserted into the medication ports of most medical equipment.